Enable native Windows on Arm build

build/toolchain/win/BUILD.gn

@@ -288,7 +288,10 @@ if (target_cpu == "arm64") {
   win_toolchains("arm64") {
     toolchain_arch = "arm64"
   }
-  win_toolchains(host_cpu) {
-    toolchain_arch = host_cpu
+  # Cross-compilation support for x64 hosts.
+  if (host_cpu != "arm64") {
+    win_toolchains(host_cpu) {
+        toolchain_arch = host_cpu
+    }
   }
 }

build/toolchain/win/setup_toolchain.py

@@ -61,12 +61,17 @@ def _SetupScript(target_cpu, sdk_dir):
     return [os.path.normpath(os.path.join(sdk_dir, 'Bin/SetEnv.Cmd')),
             '/' + target_cpu]
   else:
+    vcvars_arch = {
+        'x86': 'amd64_x86',
+        'x64': 'amd64',
+        'arm64': 'amd64_arm64',
+    }
     # We only support x64-hosted tools.
     # TODO(scottmg|dpranke): Non-depot_tools toolchain: need to get Visual
     # Studio install location from registry.
     return [os.path.normpath(os.path.join(os.environ['GYP_MSVS_OVERRIDE_PATH'],
                                           'VC/Auxiliary/Build/vcvarsall.bat')),
-            'amd64_x86' if target_cpu == 'x86' else 'amd64']
+            vcvars_arch[target_cpu]]
 
 
 def _FormatAsEnvironmentBlock(envvar_dict):

build/vs_toolchain.py

@@ -41,6 +41,12 @@
   ('2022', '17.0'),
 ])
 
+VC_VERSIONS = {
+  '2017': 'VC141',
+  '2019': 'VC142',
+  '2022': 'VC143',
+}
+
 
 def SetEnvironmentAndGetRuntimeDllDirs():
   """Sets up os.environ to use the depot_tools VS toolchain with gyp, and
@@ -247,15 +253,19 @@ def _CopyUCRTRuntime(target_dir, source_dir, target_cpu, dll_pattern, suffix):
   """Copy both the msvcp and vccorlib runtime DLLs, only if the target doesn't
   exist, but the target directory does exist."""
   if target_cpu == 'arm64':
+    env_version = GetVisualStudioVersion()
+    vc_version = VC_VERSIONS[env_version]
+    prefix = 'Microsoft.' + vc_version
+
     # Windows ARM64 VCRuntime is located at {toolchain_root}/VC/Redist/MSVC/
-    # {x.y.z}/[debug_nonredist/]arm64/Microsoft.VC141.CRT/.
+    # {x.y.z}/[debug_nonredist/]arm64/Microsoft.VC14{1,2,3}.CRT/.
     vc_redist_root = FindVCRedistRoot()
     if suffix.startswith('.'):
       source_dir = os.path.join(vc_redist_root,
-                                'arm64', 'Microsoft.VC141.CRT')
+                                'arm64', prefix + '.CRT')
     else:
       source_dir = os.path.join(vc_redist_root, 'debug_nonredist',
-                                'arm64', 'Microsoft.VC141.DebugCRT')
+                                'arm64', prefix + '.DebugCRT')
   for file_part in ('msvcp', 'vccorlib', 'vcruntime'):
     dll = dll_pattern % file_part
     target = os.path.join(target_dir, dll)